Environmental Factors Affecting the Yield of Tea (Camellia sinensis). II. Effects of Soil Temperature, Day Length, and Dry Air

SUMMARY Temperature is the major environmental variable affecting the yield of tea, but within the framework of a temperature model shoot extension is severely depressed when daily maximum vapour pressure deficits rise above 2.3 kPa. Day length does not affect shoot extension when the nights are cool (10°C), but growth rate is depressed by short days (11 h) when nights are warm (20°C). Soil temperatures between 18–25°C do not affect shoot extension.